This invention relates to devices such as electric motors (rotary, linear, or reciprocating) which use permanent magnets and electromagnetic coils.
More particularly, this invention relates to devices such as motors having flux-controlling assemblies which, during operation, cause the magnetic flux from a permanent magnet to be alternated between two or more flux paths. This is accomplished by using timed delivery of electric current through one or more electromagnetic coils which are positioned, in novel arrangements as disclosed herein, around or adjacent to at least one of the flux paths. Such flux-control assemblies may take on a variety of configurations, such as in electric motors for generating reciprocating, linear, or rotary motion, and in devices useful for voltage or power conversion.
Such devices are especially useful for rotary motors that do not require any wires, coils, or circuitry in the rotor component, and which instead use rotors containing permanent magnets, or magnetizable alloys such as steel. The motors disclosed herein do not require brushes or commutators to control current which flows through rotor coils, since there are no rotor coils.
The closest known prior art to the present invention is disclosed in U.S. Pat. Nos. 5,254,925, 5,463,263 and 5,455,474 (all issued to Flynn, or to Flynn et al). Briefly, these patents disclose various rotor and stator arrangements wherein a permanent magnet in the rotor is pulled in the desired direction of rotation, because it is magnetically attracted to a fixed and permanent stator magnet. As the rotor magnet reaches a point of closest proximity to the stator magnet, the magnetic field of the stator magnet is suddenly counteracted, or overridden, so that it effectively disappears. This is accomplished by means of a timed pulse of electrical current, which flows through an electromagnetic coil wrapped around or near the stator magnet. The current which momentarily passes through the coil generates a magnetic field that counter-balances and offsets the magnetic field of the permanent stator magnet, effectively causing it to suddenly disappear just as the rotor magnet reaches its closest proximity to it. When the attractive force generated by the permanent stator magnet suddenly disappears, the momentum of the rotor causes the rotor magnet to travel on, past the stator magnet, without being pulled back. Once the rotor magnet has traveled a certain distance, it is then attracted toward the next stator magnet lying adjacent to its ongoing path.
Although motor designs of that nature continue to hold promise, they have not yet been commercialized and made publically available, and research by Flynn et al has continued on methods and designs for increasing the torque and efficiency of motors within that general class.
As a result of that ongoing research, several methods and designs have been created which build upon a highly useful realization and discovery, to substantially improve motor performance compared to prior patented designs. Without limiting the invention by means of the following overview and summary, it has been realized and discovered that a novel and highly useful type of control method involves controlling and directing a magnetic flux generated by a permanent magnet through two alternate pathways, in an alternating manner.
In one type of motor which uses this design, one of the flux pathways is a torque-generating pathway, while the other pathway is simply a xe2x80x9cbypassxe2x80x9d, which carries the flux from the permanent magnet in the stator to a secondary position, where the flux will not interfere with rotation of the rotor when the rotor is at its point of closest proximity to the permanent magnet. It has been discovered that providing a piece of flux-carrying metal to provide this type of xe2x80x9cbypassxe2x80x9d pathway can greatly reduce the amount of electrical current and voltage that was required to counterbalance and offset the flux in the prior designs disclosed in prior U.S. Pat. Nos. 5,254,925, 5,463,263 and 5,455,474. Accordingly, the new designs and methods disclosed herein significantly improve the efficiency of the motors disclosed herein, and allow these new designs to use significantly smaller and less expensive coils, and lower voltages.
In a second type of motor disclosed herein, the use of two alternating flux pathways, under the control of one or more coils and an electronic control system, cause the magnetic flux from a permanent magnet to alternate between two different pathways, both of which can generate useful torque or linear attractive force, depending on the position of the rotor or other moving device at any particular instant. Since the flux from each permanent magnet in this class of device is constantly performing useful work, in two alternating locations, this design is even more efficient and productive than the prior systems disclosed in U.S. Pat. Nos. 5,254,925, 5,463,263 and 5,455,474, which expended electrical energy to counter-balance or offset a permanent magnet flux in a way that did not perform useful work during the intermittent stoppages of the flux.
As a result, the methods, designs, and constructions disclosed herein are substantially improved when compared to the prior art. These improved designs offer high efficiency in converting electrical energy to mechanical power and work, and also offer desirable torque and performance characteristics.
Accordingly, one object of the present invention is to provide an electromagnetic flux control assembly, which allows the path of magnetic flux from a permanent magnet to be controlled and directed in an alternating manner between two or more pathways, by means of a relatively small current at a relatively low voltage, flowing through one or more electromagnetic coils which are part of the flux control assembly.
Another object of the present invention is to provide a permanent magnet flux control assembly in which substantially all of the flux from a permanent magnet can be switched between at least two different flux paths, both of which are positioned within a device such as a motor, to enable useful work in the form of linear, reciprocating, and rotary motion.
Another object of the present invention is to provide permanent magnet flux control components and motor constructions in which flux path control is provided by energizing an electromagnet in a manner which supplements and increases the magnetic flux of one or more permanent magnets.
Yet another object of the present invention is to provide permanent magnet motor constructions having improved design, construction, operating, and electrical characteristics.
These and other objects and advantages of the present invention will become apparent after considering the following detailed specification describing several preferred embodiments in conjunction with the accompanying drawings.
A device such as a rotary or linear motor is disclosed, comprising at least one permanent magnet having north and south pole faces. A first pole piece made of a flux-carrying metal is placed adjacent the north pole face of the permanent magnet, preferably pressed directly against the magnet. The first pole piece extends beyond the perimeter of the north pole face of the magnet, to define a first flux path and a second flux path, either path capable of carrying magnetic flux emanating from the north pole face of the permanent magnet. Similarly, a second pole piece made of a flux-carrying metal is placed adjacent the south pole face of the permanent magnet, preferably pressed directly against the magnet. The second pole piece also extends beyond the perimeter of the south pole face of the magnet, to define first and second flux paths emanating from the south pole face of the permanent magnet.
At least one first control coil is positioned around the first path portion of the first pole piece, and is provided with electronic circuit control means for intermittently passing current through the coil in a time-controlled manner. If desired, a second control coil (also provided with electronic circuit control means) can also be positioned around the second path portion of the first pole piece. Alternately or additionally, one or more other control coils can also be placed around the first and/or second path portions of the second pole piece as well. The various control coils are alternatingly energized in a timed sequential manner, thereby causing the magnetic flux from the permanent magnet to be alternatingly shuttled back and forth between two different flux pathways. These two flux pathways are established by (i) the two first flux paths, established by the first and second pole pieces, acting together when appropriate, and (ii) the two second flux paths, established by the first and second pole pieces, acting together when appropriate.
By proper arrangement and assembly of the permanent magnet(s) in conjunction with the pole pieces, coil(s), and electronic circuit control means, in a manner which allows them to form a stator assembly which interacts with a rotor or other movable component that does not require any windings, brushes, or commuters, this design provides for rotary, linear, or reciprocating motors or similar devices which generate high efficiency and high torque with relatively low weight and electrical requirements, combined with various manufacturing, operating, and other advantages.